Applicant has previously developed hydraulically actuated arbor and chuck construction such as disclosed in U.S. Pat. No. 3,202,432 issued Aug. 24, 1965, which require manual or power actuation while the tool is stationary. It is known prior art to employ externally and intensified pressure to a stationary arbor or chuck such as disclosed in said patent; however, fluid pressure couplings for connecting an outside source with a rotary element have been limited to moderate maximum pressure in the order of 1000 psi compared to required actuating pressures which may be in the order of 4000 to 5000 psi.
Gas-liquid hydraulic expandable chucks and shafts having an internal closed liquid hydraulic intensifying system are disclosed in U.S. Pat. No. 4,147,312 which involve, however, the use of a removable air pressure hose to actuate the intensifying piston with the tool in a stationary condition. In any such high pressure chucks or arbors which require pressurizing with the tool stationary, the possibility of leakage resulting in a loss of holding pressure during operation with resulting slippage damaging workpiece and tool has created a long existing need for a solution which would assure maintenance of required high pressure throughout the operating cycle; also to facilitate rapid and automatic release and engagement of workpiece for production runs with positively controlled accuracy of pressure for actuation thereby facilitating automation.